1. Field of The Invention
The present invention relates to questionnaire forms and scanning systems employed with such forms and, more particularly, to a method and system for detecting marks on questionnaires.
2. Background Art
Questionnaires for testing, surveys and other purposes have been extensively used with optical mark scanning systems which have been developed to read and detect marks or the absence of marks made in designated response areas. One known system is disclosed in U.S. Pat. No. 4,937,439 to Wanninger et al wherein the survey form has a series of preprinted timing marks, located along one edge of the form, and preprinted quality assurance marks located in a predetermined relationship with the timing track for triggering the system to scan the response areas and for alignment of the response areas for printing and scanning.
In the Wanninger system as well as other known opticaI scanner systems, the accurate detection of the response areas depends largely upon the ability of the system to detect the timing marks and the accuracy in turning on the optical scanner beam at the precise locations of such response areas. Generally, these systems detect each timing mark and scan each line associated with the timing mark on a real time basis. As a result, errors in locating the response areas are caused by mechanical tolerances in the page feed mechanisms, page skew and the operation of the optical scanner. As pointed out by Wanninger, if the response areas are not printed in relatively exact alignment with the corresponding timing mark, the optical mark reading scanner may interpret the edge of a response area as a positive response or answer mark, rather than as a guide for the user filling in data or an answer mark. Such patentee creates a customized survey form with custom text printed on the form such that only the user is permitted to position the response areas about a series of locations or dots that make up a grid pattern that is aligned in a specified relation with the preprinted timing marks. The computer that operates the scanner utilizes the position data for all the response areas, including the special timing and alignment marks. Such prior art system requires the timing and alignment marks for accuracy in locating the response areas, and also is dependent on the accuracy of the scanners that utilize the response area position data in order to correctly scan the response areas. It is, therefore, desirable to have a scanning system and questionnaire therefor which do not depend on preprinted timing marks and registration marks activating a scanner for accurately locating the answer response area on a real time basis.
Also, in a Cloze type test system adapted for optical scanning and disclosed in U.S. Pat. No. 4,547,161, distractor words, forming a part of an answer, are printed at predetermined locations on a page, and programmably controlled optical scanner apparatus determines which distractor words are to be deleted from the text. Such distractor words are marked by the examinee with a printing device that generates a mark having a different reflectivity than the text. The system requires row marks along the page margin to provide synchronizing signals to enable the scanner apparatus to locate and identify the rows which are being scanned.